Gastrointestinal Disorders

Complications associated with the gastrointestinal (GI) tract are common in both infants born prematurely and at term. The immature liver and GI tract put infants at risk for diseases not encountered in older children or adults, such as benign hyperbilirubinemia and necrotizing enterocolitis. Developmental abnormalities of the GI tract can lead to surgical emergencies primarily encountered in the neonatal period.

This section covers the following topics:

Necrotizing Enterocolitis
Surgical Management of GI Disorders in Infants

Hyperbilirubinemia is covered in the Neonatal Hematology section.

Necrotizing Enterocolitis

Necrotizing enterocolitis (NEC) is a complication of prematurity, a significant cause of mortality in premature infants and a cause of multiple complications later in life. Additionally, NEC contributes significantly to NICU costs. Although NEC is primarily seen in preterm infants, term infants can also develop NEC, although not with the same pathophysiology as preterm NEC. The frequency of NEC increases as gestational age decreases. It typically occurs in the setting of enteral feeds and at least 8 to 10 days postnatally.

Pathophysiology

NEC is a multifactorial disease, and the pathophysiology is not completely understood. Risk factors include intestinal immaturity, change in microbial colonization, differences in feeding methods, and a genetic predisposition.

Presentation

Necrotizing enterocolitis can present with multiple physical exam findings including abdominal distension and discoloration, bilious emesis, bloody stools, feeding intolerance, hemodynamic instability, apnea, and bradycardia. A plain radiograph may show dilated bowel loops, a paucity of gas in the bowel, and pneumatosis intestinalis, all of which are pathognomonic of NEC. Portal venous gas and free intra-abdominal air are later findings and suggestive of bowel perforation.

[Image] — **Clinical and Radiographic Features of Necrotizing Enterocolitis**

Stages

Bell’s Criteria for Necrotizing Enterocolitis

Stage	Clinical and Radiographic Findings	Criteria for Diagnosis	Management
Stage 1 Suspected NEC	Clinical findings	Feeding intolerance Abdominal distension Blood in stool	Bowel rest (NPO) Bowel decompression Close observation Abdominal radiograph Consider blood cultures and short antibiotic course
Stage 2 Medical NEC	Clinical and radiographic findings	Pneumatosis intestinalis Portal venous gas	Bowel rest (NPO) Bowel decompression Blood culture, CBC, and antibiotics (7-10 days) Repeat abdominal radiograph
Stage 3 Surgical NEC	Clinical and radiographic findings in critically ill infant	Perforation with or without intestinal necrosis	Surgical drain placement or exploratory laparotomy with resection if necessary

Antibiotic choices include ampicillin, gentamicin, and metronidazole/clindamycin or vancomycin and piperacillin/tazobactam for treatment of common intestinal flora, anaerobic bacteria, and Staphylococcus species.

Surgical Management of GI Disorders in Infants

Many gastrointestinal abnormalities present in the neonatal period that require prompt surgical treatment. Due to improved prenatal screening, these diagnoses are often identified during prenatal ultrasound. However, some conditions can present unexpectedly postnatally.

Neonatal Anatomical Abnormalities Requiring Surgery

Anomaly	Typical Presentation	Diagnosis	Management
Esophageal atresia/ tracheoesophageal fistula	Difficulty tolerating feeds Respiratory distress Copious frothy secretions at birth	Place NG tube and obtain x- ray	Stop oral feeds (NPO) Avoid PPV Surgical anastomosis Evaluate for associated anomalies
Duodenal atresia	Vomiting Feeding intolerance	KUB x-ray demonstrating “double bubble” sign Place NG tube NPO	Surgical repair
Small bowel atresias/ obstructions (e.g., ileal atresia)	Bilious vomiting Feeding intolerance	Place NG tube and obtain x- ray Multiple air- fluid levels on KUB	Surgical repair and anastomosis
Malrotation with or without volvulus	Bilious emesis	Upper GI series	Ladd procedure
Omphalocele	Abdominal contents protruding from abdomen covered with sac	Physical exam	Silo placed over abdominal organs
Gastroschisis	Abdominal contents (typically intestines) protruding from anterior abdominal wall defect without sac	Physical exam	Silo placed over abdominal organs
Hirschsprung disease	No stool passage in first 48 hours of life	Rectal suction biopsy demonstrating no ganglion cells in colon	Colonic resection and anastomosis with dilations
Imperforate anus (with or without fistula)	No stool passage or passage of stool from fistula	Physical exam	Surgical repair
Congenital diaphragmatic hernia	Respiratory distress, scaphoid abdomen, bowel sounds in lung fields	X-ray	NPO Decompression of intestines Respiratory support ECMO if necessary Closure of defect
Pyloric stenosis	Projectile vomiting Hypochloremic metabolic alkalosis	Abdominal ultrasound	Surgical repair

Research

Landmark clinical trials and other important studies

Research

Aggressive vs. Conservative Phototherapy for Infants with Extremely Low Birth Weight

Morris BH et al. N Engl J Med 2008.

In a randomized trial of low birth weight infants, aggressive phototherapy decreased neurodevelopmental impairment, but did not decrease the combined outcome of death or neurodevelopmental impairment, compared to conservative phototherapy.

Laparotomy versus Peritoneal Drainage for Necrotizing Enterocolitis and Perforation

Moss RL et al. N Engl J Med 2006.

In this study, laparotomy was compared to a peritoneal surgical drain in infants <1500 grams with perforated necrotizing enterocolitis. No difference in the primary outcome of survival at 90 days was found between the two groups.